Basically front end products are the products you generally sell first. These normally tend to be your lower cost products.
The back end products are the more expensive products which you can offer to existing customers after you have build up goodwill with them.
The back end product should dovetail with the front end product perfectly.
So with this in mind I made a discounted mentorship offer to my existing newsletter subscribers.
Lo & behold one of my subscribers accepted the offer.
Result: $600 better off after reading one article.
Key takeaway: Develop back end products and offer them to existing customers.